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/* sys/infnan.c
*
* Copyright (C) 2001, 2004, 2007, 2010 Brian Gough
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <config.h>
#include <math.h>
#if HAVE_IEEEFP_H
#include <ieeefp.h>
#endif
#include <gsl/gsl_sys.h>
double gsl_nan (void)
{
return gsl_fdiv (0.0, 0.0);
}
double gsl_posinf (void)
{
return gsl_fdiv (+1.0, 0.0);
}
double gsl_neginf (void)
{
return gsl_fdiv (-1.0, 0.0);
}
int gsl_isnan (const double x);
int gsl_isinf (const double x);
int gsl_finite (const double x);
#if defined(_MSC_VER) /* Microsoft Visual C++ */
#include <float.h>
int
gsl_isnan (const double x)
{
return _isnan(x);
}
int
gsl_isinf (const double x)
{
int fpc = _fpclass(x);
if (fpc == _FPCLASS_PINF)
return +1;
else if (fpc == _FPCLASS_NINF)
return -1;
else
return 0;
}
int
gsl_finite (const double x)
{
return _finite(x);
}
#else
# if HAVE_DECL_ISFINITE
int
gsl_finite (const double x)
{
return isfinite(x);
}
# elif HAVE_DECL_FINITE
int
gsl_finite (const double x)
{
return finite(x);
}
# elif HAVE_IEEE_COMPARISONS
int
gsl_finite (const double x)
{
const double y = x - x;
int status = (y == y);
return status;
}
# else
# error "cannot define gsl_finite without HAVE_DECL_FINITE or HAVE_IEEE_COMPARISONS"
# endif
# if HAVE_DECL_ISNAN
int
gsl_isnan (const double x)
{
return isnan(x);
}
#elif HAVE_IEEE_COMPARISONS
int
gsl_isnan (const double x)
{
int status = (x != x);
return status;
}
# else
# error "cannot define gsl_isnan without HAVE_DECL_ISNAN or HAVE_IEEE_COMPARISONS"
# endif
# if HAVE_DECL_ISINF
int
gsl_isinf (const double x)
{
/* isinf(3): In glibc 2.01 and earlier, isinf() returns a
non-zero value (actually: 1) if x is an infinity (positive or
negative). (This is all that C99 requires.) */
if (isinf(x))
{
return (x > 0) ? 1 : -1;
}
else
{
return 0;
}
}
# else
int
gsl_isinf (const double x)
{
if (! gsl_finite(x) && ! gsl_isnan(x))
{
return (x > 0 ? +1 : -1);
}
else
{
return 0;
}
}
# endif
#endif
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